The present invention relates to improvements intended to provide a high-capacity chemical and/or radiological decontamination system, i.e. a system capable of processing at least a hundred people, possibly even several hundred people per hour.
A known approach to decontaminating persons exposed to chemicals or radiation is vigorous showering with a view to driving out contaminants present in the skin.
If a very large number of persons are contaminated simultaneously (military attack, terrorist attack, accident) special decontamination units are used to treat the people contaminated one after the other.
However, these known decontamination units, all of which are based on standard military models, have serious shortcomings which significantly limit their effectiveness.
The main drawback resides in the fact that water or soapy water is used for the decontaminating shower, dispensed from a shower head or in some cases by atomisers or misters. Water is capable of producing a low level of decontamination only and a large quantity of water needs to flow over the body of a contaminated person to completely remove the contaminating substances; if a first shower is not enough to eliminate the contamination completely, the person has to take a second shower, which delays the treatment of other persons waiting.
In practice, in order to treat a person effectively, a 5 minute shower under water is necessary, which is an extremely long time when several hundred people need to be treated as quickly as possible.
Furthermore, in certain situations, supplying the large quantity of water needed to treat several hundred or even several thousand people may be problematic.
Another crucial problem is that of storage and possibly disposing of and treating the contaminated water after showering.
In addition to the problems inherent in choosing which product to use for decontamination purposes, there are also procedural problems to contend with. Before being sent into the shower, the contaminated persons have to be undressed (any clothing and other objects being removed by another route) and then re-clothed after showering. The time taken to undress will vary considerably depending on the condition of the person: on average, it will take a conscious, fully able person some 30 seconds but can require up to 6 minutes in the case of an elderly person or someone who is incapacitated or injured. Moreover, a prolonged wait before getting to the showers can generate waves of panic and/or give rise to secondary effects which will aggravate the condition of the people involved (for example, in the case of an attack outside in sunny weather).
Finally, in order to use these known decontamination units, it is necessary to determine the agent of aggression (chemical contamination or not, radio-nuclear contamination or not, . . . ), which further delays the start of the decontamination operation or runs the risk of errors.
The currently known decontamination units have the practical capacity to treat a total of 12 to 20 persons per hour, which is meaningless when groups of several hundred or even several thousand people have been contaminated simultaneously and need to be decontaminated as quickly as possible (the efficiency of the treatment depends to a large extent on the speed with which action can be taken).
It is against the background of these circumstances that the invention proposes an improved method and system which is intended to overcome the shortcomings of currently known systems and which will enable decontamination on a large scale, i.e. will be capable of treating at least a hundred people, possibly even several hundred people per hour.
To this end, a first aspect proposed by the invention is a high-capacity process of chemical and/or radiological decontamination characterised in that it incorporates the following steps which consist in:
showering the contaminated persons individually with a regeneratable active product for a predetermined period ranging between 5 and 20 seconds,
continuously collecting the used shower liquid and
regenerating the collected liquid to restore its active capacity with a view to recycling.
By preference, the shower product used is a regeneratable active product which is amphoteric and has a chelating effect such as the product sold under the name of DIPHOTERINE, or derivatives thereof.
The advantage of using a product of this type is that it produces a decontaminating action much more quickly than water since a shower lasting for a few seconds, in practice about ten seconds, has proved to be sufficiently effective. The individual treatment of the affected persons is therefore speeded up by a ratio of 1 to 30 which, intrinsically speaking, is sufficient to make the method proposed by the invention a high-capacity procedure compared with the solutions currently used.
In addition, because it is regenerative in nature, there is no need to keep a very large stock of the shower product used for the method proposed by the invention. The product merely needs to be available in a sufficient quantity to meet a usage requirement of several tens of litres per minute, for example from 10 to 100 l/min, preferably in the order of 20 l/min. Circulating the product in a closed circuit, collecting the contaminated liquid after showering and regenerating it with a view to recycling solves both the problem of supplying a showering liquid and the problem of recovering the contaminated liquid. Once installed, the decontamination unit will therefore be able to operate for an unlimited period of time and without any constraints as to the number of persons who can be treated. It might even be conceivable to operate showers continuously as there would be no wastage at all, given that the shower product can be recuperated, and operation of the showers would be simplified (eliminating an automated on and off system); this could also help to speed up the process of getting people under the shower.
Finally, the amphoteric nature of the shower product used by preference makes this product universally applicable which will ensure effective decontamination irrespective of the nature of the contamination. It also avoids the risk of any errors of the type which can occur with the currently used systems and at the same time will considerably speed up the process of getting the decontamination unit up and running.
Using a product with chelating properties for showering enables the contaminated product to be regenerated when placed in contact with the same product which is not contaminated. Not only can the product be used in a closed circuit, the quantity of product used in such a closed loop can be kept relatively low and will only need to be topped with a small quantity of fresh product at certain times when contamination has reached a high level. In a preferred approach to implementing the method:
the liquid for each shower is drawn off from a tank,
the spent shower liquid is collected and returned to said tank,
the liquid contained in the tank is continuously agitated,
the level of contamination of the liquid contained in the tank is continuously measured and
the fresh active product introduced into the tank is adjusted to said measurement so that the liquid contained therein is fully and continuously regenerated.
In addition, by virtue of another aspect, the invention proposes a high-capacity chemical and/or radiological decontamination system capable of operating the method described above and which, in order to do so, is characterised in that it comprises:
a shower unit designed for showering persons individually with a regeneratable active product for a predetermined period ranging between 5 and 20 seconds,
means for recovering the contaminated active product from each shower unit and
a unit for regenerating the contaminated active product so that it can be recycled.
In view of the advantages explained above, the regeneratable active product used in the system described above will preferably be amphoteric and have chelating properties. Accordingly, due to the specific active nature of the product and its capacity to be regenerated rapidly, the time needed to shower individual persons can be reduced (5 to 20 seconds) and in practice a duration of some 10 seconds has been found to be sufficient. The length of showering can be automated to this timing, either by providing means (cells for example) to control activation and de-activation of the shower when a person walks into the shower and out of it respectively or, much more simply, by leaving the shower in continuous operation, which will not be a major drawback since the shower product is recovered, regenerated and recycled.
Another interesting feature is the fact that the product regeneration unit is also automated and comprises:
a tank containing the regeneratable active product,
means to link the means used to collect contaminated active product and the tank in order to return the contaminated active product to the latter,
agitation means designed to keep the product contained in the tank under constant agitation,
means for measuring the level of contamination of the active product contained in the tank,
a stock of fresh active product,
and delivery means placed under the control of said measuring means to control the delivery of fresh product to the tank in a quantity sufficient to regenerate fully all the active product contained in the tank.
By preference, the installation will incorporate means for sterilising the active product delivered to the shower unit and/or means for filtering radioactive elements will be provided downstream of the recovery means for the contaminated active product.
In a preferred embodiment, the system comprises:
a shower unit having at least two shower cubicles disposed in a central position,
at least one undressing unit comprising a plurality of individual undressing cubicles for contaminated persons and disposed on the entrance side of the shower unit,
at least one intake filtering station at the entrance arranged between the undressing unit and the shower unit so as to direct each undressed contaminated person selectively at the appropriate time to a free shower unit,
at least one dressing unit comprising a plurality of individual dressing cubicles for the showered persons located on the exit side of the shower unit, opposite the undressing unit and
at least one exit filtering station arranged between the shower unit and the dressing unit so as to direct each showered person selectively to a free dressing cubicle.
Advantageously, a decontamination station is operated for each shower cubicle to deal with the papers and personal belongings of the showered persons.
Also advantageously, the undressing unit at one end and the dressing unit at the other end are arranged so that they substantially surround the centrally positioned shower unit such that all the undressing cubicles on one side and all the dressing cubicles on the other side are located more or less at a same distance from the shower unit; accordingly, the undressing cubicles at one end and the dressing cubicles at the other end are divided into several groups of cubicles aligned side by side in a desirable layout, these groups being laid out in a broken concave line around the shower unit.
Furthermore, with a view to increasing the speed and efficiency of the treatment, it is desirable for each shower cubicle to be of the type having a plurality of jets distributed on several posts surrounding the person being showered, such a shower station optionally being of the type described in document FR 2 513 871.
This system layout offers the best possible way of making use of the advantages gained by using active products that are amphoteric and have a chelating action, enabling a large number of contaminated persons to be treated (for example 100 to 200 persons per hour) using simple equipment that can be easily and rapidly installed at a relatively low cost.